Flapper valves have been used in toilet flush tanks for some time, and all are substantially of the same construction. Such valves comprise a relatively large-area rubber member which is pivotally secured to the overflow pipe, and is pivoted by means of the usual hand-operated lever mechanism into and out of operative relation with the outlet pipe from the toilet tank. The flapper valve carries a depending ball-like member, by means of which it seats in the opening in the outlet pipe when it is in the closed position.
The ball-like member also provides a buoyancy or lift which assists the valve in raising off the outlet pipe when it is desired to have water flow out of the tank. The operation appears to be as follows. The operator manipulates the lever mechanism to move the flapper off the outlet pipe. As the flapper begins to rise and as water beings to flow out of the outlet pipe, it provides a lifting force on the ball member to raise the valve completely off the outlet pipe and to thus permit the tank to empty as required.
For proper operation and to impart suitable buoyancy and lift, the ball is made hollow and of relatively large volume. In fact, as compared to the diameter of the outlet pipe, the ball is so large that it can easily, and often does, hang up on the outlet pipe and the desired seal is not made with the outlet pipe when the valve is in the closed position. This problem is magnified when the ball ages and swells after being in water for a considerable length of time. In addition, the general efficiency of the operation of flapper valves can always be improved, and the present invention is directed toward providing such improvement.